Re: #qcxmini Ideal BPF Peak and 5v on coax center pin? #qcxmini

Ronald Taylor

Vance, that high 7 range reading is probably fine, as long as you are not at fully open or full meshed on the C1 trimmer. 

I checked my QCX just now with DC reading DVM on the BNC connector and find 5 volts on the center pin as well. But when terminated with 50 ohm dummy load it goes to zero. My guess is we are seeing the local oscillator signal from the mixer but that's just a guess. Anyone else have any ideas?? 

73 .. Ron

On Wed, Aug 18, 2021 at 10:49 AM Vance.Langer via <> wrote:
Hi everyone,
I finished up my QCX Mini (what a fantastic kit!) and noticed a few things while doing the alignment. Firstly, I was only able to set the BPF Peak to high 7, almost 8. Is this too low? Is there anything I can tweak within the hardware to improve this? The rest of the alignment went well.

Secondly, when trying to determine the power output with a DMM and the 50 ohm dummy load I noticed I could get just over 5 watts output with 13.5V in, reading off the charts in the manual. However there's a lingering 5v on the center coax pin. What's the deal there?

I got it hooked up to my EFHW for some listening, there didn't seem to be much happening on the 20m band but my antenna placement was less than ideal, I'll try again later. I did manage to listen in on a couple of QSOs and the built-in decoder seems to do well! Does anyone have recommended decoder settings that work best?

Thanks a lot everyone for the help and advice, this is an awesome group!

Join to automatically receive all group messages.